Problem description: If a trigger has 2 hosts in its expression and one of these hosts is in maintenance, then no notification is triggered if this trigger is set to problem status. According to user documentation: If at least one host (used in the trigger expression) is not in maintenance mode, Zabbix will send a problem notification

Steps to reproduce:

1. Create 2 hosts
2. Create a trigger that has both of these hosts in its expresson
3. Create a maintenance period for one of these hosts
4. Wait for the maintenance period to start
5. Set the trigger in status "Problem"

Result: Trigger is in status problem, no notification is sent out
Expected: Notification should be sent out as one of the hosts mentioned in the trigger expression is not in maintenance.